mdmStatsFailedDialAttempts
Modem Statistics Failed Dial Attempts
1.3.6.1.2.1.38.1.12.1.4
The number of call attempts that failed because the modem didn't go off hook, or there was no dialtone.
Back to rfc1696 MIB page.
IPHost Network monitor uses SNMP for monitoring health and availability of devices and applications in your network. You can send a SNMP Set to any remote device to monitor a specific SNMP object (CPU, Memory, Disk, Server Temperature, RAID failures, IO statistics, connection counts, error and much more).